Human Cardiac Tissue Repository Core. To study the immunopathogenesis of human cardiac allograft arteriosclerosis (GA), the Human Cardiovascular Tissue Repository will continue to build on the highly successful existing tissue bank established at Hopkins. The functions of the core will be: 1. To banked fresh-frozen tissues include sections of myocardium and coronary arteries. The number of hears from patients undergoing a re-transplantation have steadily been in the range of 5-15% of all hearts transplanted (average 30 hearts per year) at Hopkins during the last 10 years. The infrastructure in place for this core allows for procurement of human hearts at the time of surgery. Cardiac tissues are triaged and processed immediately as needed by the different projects in this proposal (e.e. freezing, cell culture, organ culture) by a cardiac pathologist as part of the evaluation of the specimen. In addition to the fresh and frozen tissue repository, there is formalin-fixed paraffin- embedded tissue from human heart transplant recipients, which currently includes over 6,000 heart biopsies, 54 autopsies and 223 explanted hearts, including 24 explanted from heart transplant recipients who were re- transplanted because of allograft vasculopathy in their first grafts. 2. Another function of this core be to provide clinical data striped from any identifies to individual investigators. These database is supported by departmental funds and are provided free to the Core. 3. Comprehensive pathologic examination of the tissues will be performed with advanced pathologic techniques in our facilities at Hopkins Molecular Pathology, tissues will be performed with advanced pathologic techniques in our facilities at Hopkins Molecular Pathology, Research Immunohistochemistry, and Research Histology laboratories. 4. Cardiac allograft arteriosclerosis lesions will be microdissected and analyzed with an array of ProteinChips/TM to identify protein expression alterations in the allograft important mechanism in the pathogenesis of cardiac allograft arteriosclerosis. Accordingly, the proteomics core will focus on the role of IFN-gamma and the molecules that both, regulate IFN-gamma and are regulated by IFN-gamma, leading to proliferation of TH1 cells. The proteomics core will correlate expression of molecules identified in projects 1, 2 and 3 taking advantage of phage-peptide-display libraries and candidate gene sequences identified in core E (RNA microarrays). Core D will microdissect cells from human coronary arteries. Microdissection will allow the comparison of the proliferative cell component present in the intima of GA vessels with musculopathy and smooth muscle cells from the media of transplant arteries and controls. The power of the proteomics analysis with the ProteinChipTM technology is that femtomolar amounts of proteins can be identified, thus requiring only a few hundred to a few thousand cells from human arteries to obtain protein expression information. The integration of this core with the projects in this proposal will provide scientific basis to develop effective approaches to early diagnosis of GA and provide information of possible targets for early therapeutic intervention, which is crucial to lengthen the longevity of the allograft.